You should leave 12 hours between T3 and the test. So, if you skip your evening dose, you will be leaving aout 36 hours between the test and the last dose, and that's much too long. Can you not take your T3 a little earlier the evening before the test, so as to make it a 12 hour gap?
I think knowing when to take your T3 creates a dilemma. Some say it peaks at two hours, or four hours or six hours. I have no idea but remember, this whole timing business was to get to see your highest TSH level so that doctors will not reduce your dose. That is still a good plan for T4 but realistically, I'd like to see where my FT3 is really at and not manipulate the outcome. Personally I would probably take that evening dose at the normal time. I have never read anything more definitive and I'm not a professional.
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